Photographic printer for printing stereoscopic images

ABSTRACT

A stereoscopic system includes a stereoscopic camera for exposing color negative film and a printer for printing the color negative stereo images captured by the camera onto positive color transparency film. In one example, the stereoscopic camera is a fixed exposure single use camera. A stereoscopic printer for producing stereoscopic disks includes a rotating print head for exposing a plurality of stereo image pairs in a circular pattern. A stereoscopic disk of the type that is used in a View TM -Master viewer is produced from the transparency film.

FIELD OF THE INVENTION

The present invention relates to a stereoscopic system of the typeincluding a camera for capturing stereo image pairs, photofinishingequipment and a viewer for viewing stereo image pairs. For example, asystem of the type wherein a plurality of stereo image pairs arearranged around the periphery of a disk, the images of the pairs beingarranged diametrically opposite each other on the disk, and a method ofmaking such a stereoscopic disk.

BACKGROUND OF THE INVENTION

In a well known system of stereoscopic imaging, transparent stereo imagepairs are arranged around the periphery of a disk. The stereo images areviewed by inserting the disk in a binocular viewer. Successive imagepairs are viewed by rotating the disk in the viewer, for example, byactuating a lever that engages the disk and rotates the disk by twoimage widths. Such a stereoscopic imaging system is widely available andsold under the trademark View®-Master. FIGS. 7-11 illustrate theconstruction of the conventional View®-Master disk. As shown in FIG. 7,the conventional View®-Master disk includes 14 film chips generallydesignated 10 and as shown in FIG. 8 a disk formed from six layers oflaminated paper and foil 12. The film chips 10 representing 7 stereoimage pairs 14a, b-26a, b are made from images exposed and developed on16 mm movie film, and then cut into chips. The paper and foil disk 12includes four layers of paper 28, 30, 32, and 34, and two layers of foil36, 38. The paper and foil is prelaminated into two units ofpaper-foil-paper prior to assembly of the disk. Windows 40 are cut inthe paper and foil for mounting the stereo pairs. FIG. 9 shows how thefilm chips are mounted in the paper and foil laminated disk 12. FIG. 10is an exploded cross sectional view of a completed View®-Master disktaken along line 7--7 in FIG. 9 showing how the film chips 14a, b aremounted in the windows 40 that are cut in the laminated disk. Referringback to FIG. 8, one of the weak points of the conventional View®-Masterdisk is the thin web of material 42 between the interior corners of thewindows 40 in the laminated disk 12. Because this web of material 42needs to be at least greater than some minimum dimension, the size ofthe stereo image for a given number of images, e.g. 14 images separatedby a given stereo separation x, e.g. 65 mm is limited to some maximumdimension, e.g. 10×12 mm. Although a 65 mm separation between the imagesin a stereo pair is comfortable for the average adult, a separation of55-58 mm is more appropriate for the average child. Unfortunately, ifthe separation is reduced from 65 mm to 55 mm, the webs 42 become sothin that the disk becomes too fragile for normal use. If the size ofthe images are reduced, resolution is sacrificed. FIG. 11 illustratesthe three degrees of freedom X, Y and θ in which each of the film chips14a and b must be precisely located. It will be appreciated from theforegoing description that the apparatus for assembling the stereo imagedisk must be quite complex with many moving parts. One object of thepresent invention is to provide an improved construction for a stereoimage disk that avoids the problems noted above. It would be desirableto be able to produce huge quantities of the stereoscopic disks, forexample for advertising purposes. Unfortunately, the cost of theassembly equipment is prohibitive for producing one time large batchesof the elements.

Stereoscopic systems are also known in the prior art which employspecial stereoscopic cameras to capture stereo image pairs on a filmstrip. Stereo image chips are punched from the developed film strip,using a special punch designed for use with the camera, and theresulting film chips are manually inserted into a special mounting diskwith a tweezer like tool. The special mounting disk is made from a sheetof metal covered on both sides with sheets of paper. See the descriptionof the Stereo Realist system discussed at pages 68-70 in the "The Worldof 3-D" by Jac G. Ferwerda published by 3-D Book Productions, TheNetherlands. The Stereo Realist system used color reversal film, whichhas a very narrow exposure latitude and therefore requires preciseexposure control. The cameras were generally expensive to manufactureand the related cutting and mounting hardware was expensive andcomplicated to use. It would therefore be desirable to provide amateurswith the ability to produce their own stereoscopic images, inparticular, stereoscopic disks, that could be viewed in a View®-Masterviewer, but it will be appreciated that cameras having sophisticatedexposure control and the production of the View®-Master disks as notedabove is prohibitively expensive and difficult for all but the mostdedicated amateur. It is therefore the object of the present inventionto provide an improved stereoscopic system and particularly an improvedsystem for producing stereoscopic disks that overcome the shortcomingsnoted above.

SUMMARY OF THE INVENTION

According to one aspect of the invention, the object is achieved byproviding a photographic printer for printing stereoscopic imagesincluding: a film gate for receiving a negative film strip bearing aplurality of stereo image pairs spaced along the film strip; a pair ofprinting lenses arranged to project an image of a pair of stereo imagesin said gate onto a printing plane; a print material holder for locatinga positive transparency print material in said printing plane; and amechanism for providing relative rotation between said film gate andsaid print material holder, whereby a plurality of stereo image pairsmay be printed in a circular pattern on the transparency material.

According to another aspect of the present invention, a color negativefilm is exposed in a stereoscopic camera to produce a negative filmstrip having a plurality of stereo image pairs, and the negative filmstrip is printed on a positive color transparency material to make acolor stereoscopic image employing the photographic printer according tothe present invention. The method of the present invention isparticularly suited for use with images made in a single usestereoscopic camera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded diagram showing a stereoscopic disk producedaccording to the present invention;

FIG. 2 is a cross sectional view of the stereoscopic disk shown in FIG.1 taken along lines 2--2;

FIG. 3 is a schematic diagram illustrating the method of making the diskshown in FIG. 1 and 2, according to the present invention;

FIG. 4 is a schematic perspective view of a photographic printeraccording to the present invention;

FIG. 5 is a schematic detail of the printer showing one method ofachieving an enhanced stereo effect;

FIG. 6 is a schematic detail of the printer showing an alternativemethod of achieving enhanced stereo effect;

FIG. 7 is a schematic diagram showing the seven stereo pairs of filmchips that are employed in a prior art View®-Master stereoscopic disk;

FIG. 8 is an exploded diagram showing the six laminations of foil andpaper employed in the prior art View®-Master stereoscopic disk;

FIG. 9 is a schematic diagram showing how the film chips of FIG. 4 arearranged in the View®-Master stereoscopic disk;

FIG. 10 is a cross sectional view of a prior art View®-Master disk takenalong lines 7--7 in FIG. 6;

FIG. 11 is a schematic diagram illustrating the alignment of the filmchips in the prior art View®-Master stereoscopic disk;

FIG. 12 is a perspective view of a single use stereoscopic camera usefulwith the present invention

FIG. 13 is a schematic diagram illustrating the viewfinder optics of thesingle use camera shown in FIG. 12;

FIG. 14 is a schematic diagram illustrating the use of the camera shownin FIG. 12; and

FIG. 15 is a schematic diagram illustrating the film advance mechanismof the camera shown in FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, an exploded view of a stereoscopic disk 50 madewith a printer according to the present invention. The stereoscopic disk50 includes a disk 52 of photographic film having a plurality of stereoimage pairs 54 arranged around the periphery of the disk in the patternwell known in the art. The film disk 52 is sandwiched between two opaquedisks 56 and 58 having windows 60 in which the stereo images 54 arepositioned. The opaque disks 56 and 58 are preferably adhesive backedpaper but may be formed from an opaque sheet of material such as plasticor metal. The film disk 52 and the opaque disks 56 and 58 are laminatedtogether to form the stereoscopic disk which closely resembles the priorart View®-Master disk but as can be appreciated, is of much simpler andmore rugged construction. A series of detent slots 62 are arrangedaround the periphery of the disk for locating and rotating the disk in aviewer as is well known in the art. Titles 64 may be provided on thecentral region of the opaque disk 58 describing the scenes on the disk,as is well known in the art.

FIG. 2 shows a cross section of the stereoscopic disk 50 taken alonglines 2--2 in FIG. 1. Since the webs 66 of material in the opaque diskbetween the inside corners of the windows 60 are not required forphysical integrity of the completed disk 50, they may be as narrow asdesired. The images 54 of the stereoscopic disk 50 may be up to 20%larger in both the horizontal and vertical dimensions than the standardsize View®-Master disk while still maintaining the same separationbetween images in a stereo pair. Furthermore, since the webs 66 are notneeded for mechanical strength of the disk 50, a small "child sized"disk having a stereo-spacing of 55-58 mm may be constructed having thesame number and size of images as the standard size View®-Master disk,thereby preserving the resolution of the images.

Referring now to FIG. 3, the method of making the film disk 54 accordingto the present invention will be described. First, a color negative film68 such as Kodacolor 100 color negative film is exposed in astereoscopic camera 70. The stereo image pairs 1L, 1R; 2L, 2R (where Land R indicate left and right images of a pair, respectively) areinterlaced on the film 68 as is well known in the art. After processingto develop the images on film strip 68, the color negative images areprinted on a wide strip of color transparency film 70 such as Vericolorprint film in a special rotary printer 72 described in detail below. Therotary printer 72 exposes the stereo image pairs from this film strip 68in a circular pattern of stereo image pairs 54 on the print film 70. Theprint film 70 is developed in a film processor 74. The developed printfilm 70 is then punched and laminated between strips of adhesive backedpaper 80, 82, having pre-cut circular patterns of windows 60. A punch 76cuts through the paper strip 80 against a die 77, then cuts through thefilm 70 against a die 78 and finally cuts through the paper strip 82against a die 79. Punches 81 located at the bottom of the stroke ofpunch 76 form the periphery slots 62 in the completed stereoscopic disk50. The circular patterns of stereo images 54 are aligned in the windows60 in the paper strips 80,82. The resulting stereoscopic disk 50 can beused in any existing View®-Master viewer.

Referring now to FIG. 4, the printer 72 according to the presentinvention will be described in more detail. The printer 72 includes alamp house 88 for illuminating a stereo image pair 90 on a film strip68. The lamphouse 88 may be either an additive or subtractive lamphouseas is well known in the art. Film strip 68 is positioned in a film gate92. The film strip 68, comprising for example, a plurality of splicedtogether film strips is advanced in the direction of arrow A betweenexposures from a supply 94 to a take-up 96. A pair of printer lenses 98,100 project an image of the stereo image pair 90 through a shutter 102onto the transparency film 70. A conventional printer exposure controlcircuit(not shown) controls the exposure of the printer to compensatefor over and under exposure in the camera. The transparency film 70 isadvanced in the direction of arrow B from a supply 104 to a take-up 106after a series of exposures is completed. The transparency film 70 isheld in the image plane of lenses 98, 100 by a print material holder108. The film strip supply 94 and take-up 96, the lenses 98 and 100, andthe shutter 102 are mounted on a rotating platform 110 which can berotated in the direction of arrow C by a drive motor 112. A timing belt114 meshes with a driving gear 115 and a ring gear 116 on the peripheryof platform 110 to drive the platform. The timing belt is preferred tominimize the shock to the optical components during rotation.

In operation, after a stereo pair of images 90 on film strip 68 isprinted onto the transparency film 70, the film strip 68 is advanced tothe next stereo image pair in the direction of arrow A, the rotatingplatform 110 is rotated by a desired amount (e.g. two frames), and thenext stereo pair of images is exposed. This process is repeated until acomplete circle of images is exposed onto the transparency film 70. Forexample, for the View®-Master format seven stereo image pairs areexposed in one circle. The transparency film 70 is advanced in thedirection of arrow B, and the next series of stereo image pairs isexposed.

It is possible to adjust the stereo window and to enhance the effect ofthe stereo image by exposing the original images in a camera having alens and image separation greater than the final separation on the disk.For example, if a lens separation of 70 mm and image separation of 71.25mm is employed in the camera, and the stereo image pairs are printed andviewed at a separation of 65 mm, an enhanced stereo effect will result.One way of achieving the reduced separation in the printer is shown inFIG. 5, where a ramp 117 is provided in the printer 72. The film 68 goesover the ramp 117 to reduce the spacing between the images 90 on thefilm strip 68. Alternatively, as shown in FIG. 6, the images 90 can beprinted off axis in the lenses 98 and 100 to cause the images on thetransparency film 70 to be closer together than the images 90 on thenegative film, strip 68.

By using a color negative film in the stereoscopic camera, and printingonto a positive color transparency film, the wide exposure latitude ofcolor negative photographic systems may be exploited, while stillobtaining stereoscopic transparencies. Exposure correction isaccomplished in the printer using well known additive or subtractiveprinter exposure control systems. The resulting wide exposure latitudesystem enables the original stereoscopic image to be captured in aninexpensive camera having a fixed exposure, such as a single use camera,i.e. a camera that is loaded with film when purchased, and is returnedto a photofinisher for processing. FIG. 12 is a perspective view of asingle use camera 118, having a pair of taking lenses 120, 122 separatedby a distance of, for example, 70 mm. A pair of two element view finderlenses 124, 126, one for each eye, each having a primary lens 132separated by 70 mm and an eye lens 134 separated by 65 mm, as shown inFIG. 13, allow parallax free viewing of the photographic scene whileproviding the enhanced stereo images that will be seen in the finaldisplay. The double view finder also helps the photographer avoidtilting the camera during exposure. The viewfinder lenses 124,126 arearranged at the bottom of the camera for ease of use by the photographeras shown in FIG. 14. The camera 118 has a shutter release 128. A filmadvance wheel or lever 130 protruding from the back of the camera allowsthe film to be advanced by the desired distance between frames. Forexample, for 35 mm film, the film is advanced by 10 perforations betweenthe frames with a frame size of 24 mm high by 23.25 mm wide. As shown inFIG. 15, a film advance sprocket 136 which engages the sprocket holes in35 mm film 68 and undergoes one complete rotation upon film advance has10 sprocket teeth 138.

The camera can be provided with either enough film for a single disk(e.g. seven stereo pair exposures) or for multiple stereoscopic disk(e.g. 7, 14 or 21 stereo pair exposures) for 1, 2 or 3 disksrespectively.

    ______________________________________                                        PARTS LIST                                                                    ______________________________________                                         10           film chips                                                       12           laminated paper and foil layers                                  14a,b        stereo image pair                                                16a,b        stereo image pair                                                18a,b        stereo image pair                                                20a,b        stereo image pair                                                22a,b        stereo image pair                                                24a,b        stereo image pair                                                26a,b        stereo image pair                                                28           paper layer                                                      30           paper layer                                                      32           paper layer                                                      34           paper layer                                                      36           foil layer                                                       38           foil layer                                                       40           windows                                                          42           web of material                                                  50           stereoscopic disk                                                52           photographic film disk                                           54           stereo image pairs                                               56           opaque disk                                                      58           opaque disk                                                      60           windows                                                          62           detent slots                                                     64           titles                                                           66           webs                                                             68           color negative film                                              70           color print film                                                 72           rotary printer                                                   74           film processor                                                   76           punch                                                            77           die                                                              78           die                                                              80           paper strip                                                      82           paper strip                                                      86           punch                                                            88           lamp house                                                       90           stereo image pair                                                92           film gate                                                        94           supply                                                           96           take-up                                                          98           printer lens                                                    100           printer lens                                                    102           shutter                                                         104           supply                                                          106           take-up                                                         108           print material holder                                           110           rotating platform                                               112           drive motor                                                     114           timing belt                                                     115           driving gear                                                    116           ring gear                                                       117           ramp                                                            118           single use camera                                               120           taking lens                                                     122           taking lens                                                     124           view finder                                                     126           view finder                                                     128           shutter release                                                 130           advance wheel                                                   132           primary viewfinder lens                                         134           eye lens                                                        136           film advance sprocket                                           138           sprocket teeth                                                  ______________________________________                                    

We claim:
 1. A photographic printer for printing stereoscopic images,comprising:a. a film gate for receiving a film strip bearing a pluralityof stereoscopic image pairs spaced along said film strip; b. a pair ofprinting lenses arranged to project an image of a pair of stereo imagesin said gate onto a printing plane; c. a print material holder forlocating a transparency print material in said printing plane; and d. amechanism for providing relative rotation between said film gate andsaid print material holder, whereby a plurality of stereo image pairsare printed in a circular pattern on said transparency print material.2. The photographic printer claimed in claim 1, further comprising meansfor reducing the separation between stereo image pairs in the printedstereo images.
 3. The photographic printer claimed in claim 2, whereinsaid means for reducing separation is a ramp over which the film passes.4. The photographic printer claimed in claim 2, wherein said means forreducing separation is provided by printing said stereo images off axistoward each other.